var value = {};
console.log(Number(value));


value = {valueof:function(){return true;}};
console.log(Number(value));


value = {valueof(){return 18}};
console.log(Number(value));

var x = "w";
console.log(typeof +x);
console.log(x);
console.log(+x);

console.log(parseInt(" 8a:"));
console.log(parseInt(22.5));
console.log(parseInt("wang8:"));
console.log(parseInt(""));
console.log("=============================================");

var value = "";
console.log(Number(value));
console.log(parseInt(value));
console.log(parseFloat(value));

console.log(parseInt("0xff",16));

var age = 18;
var ageString = age.toString();
var found = true;
console.log(found);
console.log(age.toString(2));
console.log(String(age));


console.log("=============================================");
var result = 15;
var str = result.toString(16);
var resp = parseInt(str,16);
console.log(str);
console.log(resp);


console.log("=============================================");
console.log(typeof null);

var str = new String("w");
var o = new Object();
console.log(o instanceof Object);
console.log(o instanceof String);
console.log(str instanceof String);
console.log(str instanceof Object);
console.log(str instanceof String);

console.log("=============================================");
var color = new Array(3,4,5);
console.log(typeof color);
console.log(color instanceof Object);
console.log(color instanceof Array);

console.log(1+{});
console.log("2"+3);
console.log(1+null);
console.log(1+undefined);

console.log(8-{toString(){return 2}});






















